I think yes. On good days it's too sad to let him leave. Only way to see him in Bulls uniform next season if no other team want to overpay him.
If you assume that Hoiberg will be back (I do), Mirotic hasn't exactly blossomed under Hoiberg's coaching. Despite the fact that Mirotic has had an off year, 32% from 3 doesn't exactly scream primo stretch 4, most predict that he'll command at least $10mil/season this summer. It's likely that some other team will think more highly of Mirotic tha the Bulls do.
You two are probably right, but damn... The last few games he has looked very good offensively. Trouble with that is he has had a lot of games where he has not played well.